From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0155FC43461 for ; Tue, 15 Sep 2020 06:24:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0D9382076C for ; Tue, 15 Sep 2020 06:24:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0D9382076C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gondor.apana.org.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2A9EF90000A; Tue, 15 Sep 2020 02:24:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 25B496B007D; Tue, 15 Sep 2020 02:24:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1233890000A; Tue, 15 Sep 2020 02:24:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0139.hostedemail.com [216.40.44.139]) by kanga.kvack.org (Postfix) with ESMTP id F009B6B0078 for ; Tue, 15 Sep 2020 02:24:08 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id AA205181AEF15 for ; Tue, 15 Sep 2020 06:24:08 +0000 (UTC) X-FDA: 77264305776.17.frogs63_2a096e72710f Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin17.hostedemail.com (Postfix) with ESMTP id 73EB8180D0181 for ; Tue, 15 Sep 2020 06:24:08 +0000 (UTC) X-HE-Tag: frogs63_2a096e72710f X-Filterd-Recvd-Size: 4372 Received: from fornost.hmeau.com (helcar.hmeau.com [216.24.177.18]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Tue, 15 Sep 2020 06:24:07 +0000 (UTC) Received: from gwarestrin.arnor.me.apana.org.au ([192.168.0.7]) by fornost.hmeau.com with smtp (Exim 4.92 #5 (Debian)) id 1kI4Mf-0007aN-HK; Tue, 15 Sep 2020 16:22:54 +1000 Received: by gwarestrin.arnor.me.apana.org.au (sSMTP sendmail emulation); Tue, 15 Sep 2020 16:22:53 +1000 Date: Tue, 15 Sep 2020 16:22:53 +1000 From: Herbert Xu To: Ard Biesheuvel Cc: Linus Torvalds , Thomas Gleixner , LKML , linux-arch , Sebastian Andrzej Siewior , Valentin Schneider , Richard Henderson , Ivan Kokshaysky , Matt Turner , alpha , Jeff Dike , Richard Weinberger , Anton Ivanov , linux-um , Brian Cain , linux-hexagon@vger.kernel.org, Geert Uytterhoeven , linux-m68k , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Will Deacon , Andrew Morton , Linux-MM , Ingo Molnar , Russell King , Linux ARM , Chris Zankel , Max Filippov , linux-xtensa@linux-xtensa.org, Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie , Daniel Vetter , intel-gfx , dri-devel , "Paul E. McKenney" , Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Shuah Khan , rcu@vger.kernel.org, "open list:KERNEL SELFTEST FRAMEWORK References: <20200914204209.256266093@linutronix.de> <871rj4owfn.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspamd-Queue-Id: 73EB8180D0181 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Sep 15, 2020 at 09:20:59AM +0300, Ard Biesheuvel wrote: > > The documentation of kmap_atomic() states the following: > > * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap > * gives a more generic (and caching) interface. But kmap_atomic can > * be used in IRQ contexts, so in some (very limited) cases we need > * it. > > so if this is no longer accurate, perhaps we should fix it? This hasn't been accurate for at least ten years :) > But another reason I tried to avoid kmap_atomic() is that it disables > preemption unconditionally, even on 64-bit architectures where HIGHMEM > is irrelevant. So using kmap_atomic() here means that the bulk of > WireGuard packet encryption runs with preemption disabled, essentially > for legacy reasons. Agreed. We should definitely fix that. Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 88E1EC2D0E0 for ; Tue, 15 Sep 2020 07:07:53 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D12E1206C9 for ; Tue, 15 Sep 2020 07:07:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D12E1206C9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gondor.apana.org.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id CC80D6E84F; Tue, 15 Sep 2020 07:07:21 +0000 (UTC) Received: from fornost.hmeau.com (helcar.hmeau.com [216.24.177.18]) by gabe.freedesktop.org (Postfix) with ESMTPS id CECBA6E088; Tue, 15 Sep 2020 06:24:25 +0000 (UTC) Received: from gwarestrin.arnor.me.apana.org.au ([192.168.0.7]) by fornost.hmeau.com with smtp (Exim 4.92 #5 (Debian)) id 1kI4Mf-0007aN-HK; Tue, 15 Sep 2020 16:22:54 +1000 Received: by gwarestrin.arnor.me.apana.org.au (sSMTP sendmail emulation); Tue, 15 Sep 2020 16:22:53 +1000 Date: Tue, 15 Sep 2020 16:22:53 +1000 From: Herbert Xu To: Ard Biesheuvel Subject: Re: [patch 00/13] preempt: Make preempt count unconditional Message-ID: <20200915062253.GA26275@gondor.apana.org.au> References: <20200914204209.256266093@linutronix.de> <871rj4owfn.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Mailman-Approved-At: Tue, 15 Sep 2020 07:07:18 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , Peter Zijlstra , Sebastian Andrzej Siewior , Lai Jiangshan , dri-devel , Ben Segall , Linux-MM , linux-hexagon@vger.kernel.org, Will Deacon , Ingo Molnar , Anton Ivanov , linux-arch , Vincent Guittot , Brian Cain , Richard Weinberger , Russell King , "open list:KERNEL SELFTEST FRAMEWORK" , David Airlie , Ingo Molnar , Geert Uytterhoeven , Mel Gorman , intel-gfx , Matt Turner , Valentin Schneider , linux-xtensa@linux-xtensa.org, Shuah Khan , "Paul E. McKenney" , Jeff Dike , linux-um , Josh Triplett , Steven Rostedt , rcu@vger.kernel.org, linux-m68k , Ivan Kokshaysky , Rodrigo Vivi , Thomas Gleixner , Dietmar Eggemann , Linux ARM , Richard Henderson , Chris Zankel , Max Filippov , Daniel Bristot de Oliveira , LKML , alpha , Mathieu Desnoyers , Andrew Morton , Linus Torvalds Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Tue, Sep 15, 2020 at 09:20:59AM +0300, Ard Biesheuvel wrote: > > The documentation of kmap_atomic() states the following: > > * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap > * gives a more generic (and caching) interface. But kmap_atomic can > * be used in IRQ contexts, so in some (very limited) cases we need > * it. > > so if this is no longer accurate, perhaps we should fix it? This hasn't been accurate for at least ten years :) > But another reason I tried to avoid kmap_atomic() is that it disables > preemption unconditionally, even on 64-bit architectures where HIGHMEM > is irrelevant. So using kmap_atomic() here means that the bulk of > WireGuard packet encryption runs with preemption disabled, essentially > for legacy reasons. Agreed. We should definitely fix that. Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 22124C43461 for ; Tue, 15 Sep 2020 06:24:28 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7ACF820829 for ; Tue, 15 Sep 2020 06:24:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7ACF820829 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gondor.apana.org.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B77596E088; Tue, 15 Sep 2020 06:24:26 +0000 (UTC) Received: from fornost.hmeau.com (helcar.hmeau.com [216.24.177.18]) by gabe.freedesktop.org (Postfix) with ESMTPS id CECBA6E088; Tue, 15 Sep 2020 06:24:25 +0000 (UTC) Received: from gwarestrin.arnor.me.apana.org.au ([192.168.0.7]) by fornost.hmeau.com with smtp (Exim 4.92 #5 (Debian)) id 1kI4Mf-0007aN-HK; Tue, 15 Sep 2020 16:22:54 +1000 Received: by gwarestrin.arnor.me.apana.org.au (sSMTP sendmail emulation); Tue, 15 Sep 2020 16:22:53 +1000 Date: Tue, 15 Sep 2020 16:22:53 +1000 From: Herbert Xu To: Ard Biesheuvel Message-ID: <20200915062253.GA26275@gondor.apana.org.au> References: <20200914204209.256266093@linutronix.de> <871rj4owfn.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Subject: Re: [Intel-gfx] [patch 00/13] preempt: Make preempt count unconditional X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , Peter Zijlstra , Sebastian Andrzej Siewior , Lai Jiangshan , dri-devel , Ben Segall , Linux-MM , linux-hexagon@vger.kernel.org, Will Deacon , Ingo Molnar , Anton Ivanov , linux-arch , Brian Cain , Richard Weinberger , Russell King , "open list:KERNEL SELFTEST FRAMEWORK" , David Airlie , Ingo Molnar , Geert Uytterhoeven , Mel Gorman , intel-gfx , Matt Turner , Valentin Schneider , linux-xtensa@linux-xtensa.org, Shuah Khan , "Paul E. McKenney" , Jeff Dike , linux-um , Josh Triplett , Steven Rostedt , rcu@vger.kernel.org, linux-m68k , Ivan Kokshaysky , Thomas Gleixner , Dietmar Eggemann , Linux ARM , Richard Henderson , Chris Zankel , Max Filippov , Daniel Bristot de Oliveira , LKML , alpha , Mathieu Desnoyers , Andrew Morton , Linus Torvalds Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, Sep 15, 2020 at 09:20:59AM +0300, Ard Biesheuvel wrote: > > The documentation of kmap_atomic() states the following: > > * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap > * gives a more generic (and caching) interface. But kmap_atomic can > * be used in IRQ contexts, so in some (very limited) cases we need > * it. > > so if this is no longer accurate, perhaps we should fix it? This hasn't been accurate for at least ten years :) > But another reason I tried to avoid kmap_atomic() is that it disables > preemption unconditionally, even on 64-bit architectures where HIGHMEM > is irrelevant. So using kmap_atomic() here means that the bulk of > WireGuard packet encryption runs with preemption disabled, essentially > for legacy reasons. Agreed. We should definitely fix that. Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 15 Sep 2020 16:22:53 +1000 From: Herbert Xu Subject: Re: [patch 00/13] preempt: Make preempt count unconditional Message-ID: <20200915062253.GA26275@gondor.apana.org.au> References: <20200914204209.256266093@linutronix.de> <871rj4owfn.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: To: Ard Biesheuvel Cc: Linus Torvalds , Thomas Gleixner , LKML , linux-arch , Sebastian Andrzej Siewior , Valentin Schneider , Richard Henderson , Ivan Kokshaysky , Matt Turner , alpha , Jeff Dike , Richard Weinberger , Anton Ivanov , linux-um , Brian Cain , linux-hexagon@vger.kernel.org, Geert Uytterhoeven , linux-m68k , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Will Deacon , Andrew Morton , Linux-MM , Ingo Molnar , Russell King , Linux ARM , Chris Zankel , Max Filippov , linux-xtensa@linux-xtensa.org, Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie , Daniel Vetter , intel-gfx , dri-devel , "Paul E. McKenney" , Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Shuah Khan , rcu@vger.kernel.org, "open list:KERNEL SELFTEST FRAMEWORK" List-ID: On Tue, Sep 15, 2020 at 09:20:59AM +0300, Ard Biesheuvel wrote: > > The documentation of kmap_atomic() states the following: > > * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap > * gives a more generic (and caching) interface. But kmap_atomic can > * be used in IRQ contexts, so in some (very limited) cases we need > * it. > > so if this is no longer accurate, perhaps we should fix it? This hasn't been accurate for at least ten years :) > But another reason I tried to avoid kmap_atomic() is that it disables > preemption unconditionally, even on 64-bit architectures where HIGHMEM > is irrelevant. So using kmap_atomic() here means that the bulk of > WireGuard packet encryption runs with preemption disabled, essentially > for legacy reasons. Agreed. We should definitely fix that. Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt From mboxrd@z Thu Jan 1 00:00:00 1970 From: Herbert Xu Subject: Re: [patch 00/13] preempt: Make preempt count unconditional Date: Tue, 15 Sep 2020 16:22:53 +1000 Message-ID: <20200915062253.GA26275@gondor.apana.org.au> References: <20200914204209.256266093@linutronix.de> <871rj4owfn.fsf@nanos.tec.linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Ard Biesheuvel Cc: Juri Lelli , Peter Zijlstra , Sebastian Andrzej Siewior , Lai Jiangshan , dri-devel , Ben Segall , Linux-MM , linux-hexagon@vger.kernel.org, Will Deacon , Ingo Molnar , Anton Ivanov , linux-arch , Brian Cain , Richard Weinberger , Russell King , "open list:KERNEL SELFTEST FRAMEWORK" , David Airlie , Ingo Molnar , Geert Uytterhoeven , Mel Gorman , intel-gfx , Matt Turner , Valentin Schneider On Tue, Sep 15, 2020 at 09:20:59AM +0300, Ard Biesheuvel wrote: > > The documentation of kmap_atomic() states the following: > > * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap > * gives a more generic (and caching) interface. But kmap_atomic can > * be used in IRQ contexts, so in some (very limited) cases we need > * it. > > so if this is no longer accurate, perhaps we should fix it? This hasn't been accurate for at least ten years :) > But another reason I tried to avoid kmap_atomic() is that it disables > preemption unconditionally, even on 64-bit architectures where HIGHMEM > is irrelevant. So using kmap_atomic() here means that the bulk of > WireGuard packet encryption runs with preemption disabled, essentially > for legacy reasons. Agreed. We should definitely fix that. Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt